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Can you undress a black hole? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Jorgey, do you ever feel guilty when we send
0:11
Speaker 1: a probe to go poking around another planet? Guilty? What
0:14
Speaker 1: do you mean guilty? I think we're just being curious, right,
0:17
Speaker 1: I don't know. It's a bit presumptuous and forward, you know,
0:20
Speaker 1: like what if I sent a drone into your house
0:22
Speaker 1: to take pictures and samples? I see you mean, like
0:24
Speaker 1: for me, we're disregarding the planets privacy. Yeah, like maybe
0:28
Speaker 1: we should give them some morning so at least they
0:30
Speaker 1: can get dressed before we show up with our cameras,
0:32
Speaker 1: or maybe undressed, you know, maybe that's what they prefer.
0:36
Speaker 1: That makes me wonder what an embarrassed alien looks like anyway,
0:39
Speaker 1: and what account is not safe for work? I am
0:57
Speaker 1: R Handy cartoonists and the creator of pH D com Hi.
1:00
Speaker 1: I'm Daniel. I'm a particle physicist and I always get
1:03
Speaker 1: dressed for work. Oh nice, that's a good disclaimer to
1:07
Speaker 1: make in public. Even these days when everything is remote,
1:11
Speaker 1: you still got to put your pants on when you
1:13
Speaker 1: get started on your day, you know what I mean?
1:15
Speaker 1: Known as the naked physicists, I definitely do not want
1:17
Speaker 1: to be known for that. Absolutely not naked and Curious
1:20
Speaker 1: could be the name of the reality show Daniel Naked Curiosity.
1:25
Speaker 1: There you go, but welcome to our podcast. Daniel and
1:28
Speaker 1: Jorge explain the Universe Wearing Clothes, a production of I
1:32
Speaker 1: Heart Radio, in which we try to strip the mystery
1:35
Speaker 1: for everything in the universe. We try to find everything
1:38
Speaker 1: that makes you curious and peel back the layers, undressing
1:42
Speaker 1: the confusion and addressing your questions and trying to make
1:46
Speaker 1: sure that everything in the universe makes sense to you
1:49
Speaker 1: and give you the bare facts about the cosmos and
1:53
Speaker 1: everything in it, all the amazing things and all of
1:55
Speaker 1: the mysterious things, and also the things that we don't
1:59
Speaker 1: know if they exist. That's right, because we have two
2:01
Speaker 1: ways to get surprised in our universe. One is to
2:04
Speaker 1: go out there and see weird stuff that just doesn't
2:07
Speaker 1: make any sense to us until we can wrap our
2:09
Speaker 1: minds around it. And the other is to think of
2:11
Speaker 1: weird stuff, what if this kind of thing exists? What
2:14
Speaker 1: if that kind of thing exists? Is this even possible?
2:17
Speaker 1: And then to go out and look for it. Yeah,
2:19
Speaker 1: because a lot of times it seems like the math
2:22
Speaker 1: tells us what can exist, and oftentimes we actually go
2:26
Speaker 1: out there and find it. That's right. There's lots of
2:28
Speaker 1: times when we make a mathematical theory that describes something
2:31
Speaker 1: we see in the universe, and then we explore the
2:34
Speaker 1: corners of it. We say, well, if these rules are real,
2:37
Speaker 1: what else do they predict? What else should we be
2:39
Speaker 1: looking for? And you know, some people think that the
2:42
Speaker 1: universe is mathematical, that these rules are the ones that
2:45
Speaker 1: control the universe, and so if they have a wrinkle
2:48
Speaker 1: in them that predicts something weird, that might actually be real.
2:51
Speaker 1: So if you are not into math, we have news
2:54
Speaker 1: for you. You might be in math. As you might
2:57
Speaker 1: be math, math might be you. Yeah. And and I
3:01
Speaker 1: think a big example of that idea of thinking of
3:04
Speaker 1: something first and then discovering is black holes. Right. Black
3:08
Speaker 1: holes were first theorized by Einstein, and then people wondered
3:13
Speaker 1: about it for a long time, and then we started
3:14
Speaker 1: finding evidence for them, and then we actually just recently
3:17
Speaker 1: took a picture of a black hole. Yeah, And more
3:19
Speaker 1: than just wondered about them, people disregarded them for a
3:22
Speaker 1: long time. People figured like, well, that can't be real.
3:25
Speaker 1: That's evidence that there's something wrong with our theory. For
3:27
Speaker 1: our theory predicts something as absurd and as crazy as
3:31
Speaker 1: a black hole has got to be something wrong with it,
3:34
Speaker 1: But then of course they found it, and so the
3:36
Speaker 1: theory is not wrong, and that teaches you to follow
3:38
Speaker 1: the math. And this happens all the time, even in
3:41
Speaker 1: quantum mechanics, where we say, look, quantum mechanics predicts this
3:45
Speaker 1: totally absurd thing that could never really be real, and
3:48
Speaker 1: then you go out and you do the experiment and boom,
3:50
Speaker 1: it actually israel and the universe is as weird and
3:53
Speaker 1: as mathematical as we thought. Does that mean humans are
3:56
Speaker 1: not as weird as we should be? Do you think,
3:59
Speaker 1: like maybe we just to think weirder. Yeah, I think
4:02
Speaker 1: that's definitely true. I think of all the various layers
4:05
Speaker 1: of reality, the one we live in is the least weird.
4:08
Speaker 1: I mean, we live in this sort of large stuff
4:10
Speaker 1: that's not quantum mechanical and the slow stuff that's not relativistic,
4:14
Speaker 1: and so our corner of the universe is sort of
4:17
Speaker 1: very unweird, and if we were much much smaller or
4:20
Speaker 1: much much faster than physics would be much much weirder.
4:23
Speaker 1: Maybe that's just a perspective kind of thing, though, right, Maybe,
4:26
Speaker 1: like if we were smaller or bigger. We might think
4:30
Speaker 1: that's normal and our size is weird. Yeah, that's a
4:33
Speaker 1: difficult mental inversion, but you're right, it might be weird
4:36
Speaker 1: to think, Oh, my gosh, velocities add linearly in objects
4:40
Speaker 1: have like smooth trajectories. How bizarre is that? It's hard
4:44
Speaker 1: to put yourself in that frame of mind because this
4:46
Speaker 1: is the only one we've ever had. But that's exactly
4:49
Speaker 1: the point that physics tries to take us out of
4:51
Speaker 1: our familiar frame of mind and make us realize that
4:54
Speaker 1: the way we see the universe is limited, and the
4:57
Speaker 1: way the universe really is could be vastly to friends,
5:00
Speaker 1: And that's why we do these sort of mental and
5:02
Speaker 1: physical explorations. And black holes are weird, right, They are
5:06
Speaker 1: one of the weirdest things in the universe, and they
5:08
Speaker 1: are definitely very weird. They are little pockets of mystery,
5:12
Speaker 1: and one of the weirdest things about them is that
5:13
Speaker 1: we cannot see what's in them. We can't go inside
5:17
Speaker 1: a black hole or look inside a black hole, or
5:19
Speaker 1: get any information from what's going on inside the black
5:22
Speaker 1: hole to learn about these crazy corners of the universe. Yeah,
5:26
Speaker 1: because what's weird about them is what's inside the actual
5:29
Speaker 1: black hole? Right? What they call the singularity? That's right.
5:31
Speaker 1: General relativity at least predicts a singularity inside the black hole,
5:36
Speaker 1: although many other theories of physics, likede quantum mechanics objects
5:39
Speaker 1: to the existence of a singularity, and various mathematicians suggest
5:43
Speaker 1: the singularities are impossible in a physical universe. So then
5:47
Speaker 1: the question is what is inside the black hole? Yeah,
5:50
Speaker 1: there's a question of whether singularities can even exist, and
5:54
Speaker 1: unfortunately we can't see the ones inside of a black hole.
5:57
Speaker 1: So the question then is is it possible to see
5:59
Speaker 1: a singularity outside of a black hole or a singularity
6:03
Speaker 1: that's not a black hole? Yeah? Is it possible to
6:07
Speaker 1: uncloak the singularity, to strip away the event horizon so
6:10
Speaker 1: that as an observer you could directly see with your
6:13
Speaker 1: own eyes this bizarre thing, this singularity of space. Such
6:18
Speaker 1: a really fun, fascinating question. So to be on the podcast,
6:20
Speaker 1: we'll be asking the question what is a naked singularity
6:31
Speaker 1: and why doesn't it have any singular clothes? Even just
6:35
Speaker 1: one pair of pants? Right, if it's a singularity, should
6:37
Speaker 1: have one of everything, supposed to physicist who were three
6:41
Speaker 1: pants or four hats? At a time. That's right, And
6:46
Speaker 1: I love this name naked singularity. I mean, of course
6:48
Speaker 1: there's the slight blush factor, but also it invokes this
6:51
Speaker 1: sense that we could like really peel back the layers
6:54
Speaker 1: of the universe and see the truth, the bare naked
6:57
Speaker 1: truth of what's going on with space time. I guess
7:00
Speaker 1: the question is, we don't even know if a singularity
7:03
Speaker 1: is possible in our universe. I mean, it's theorized inside
7:07
Speaker 1: of a black hole, but you can't see inside of
7:09
Speaker 1: the black hole. Yeah, that's right, And so this is
7:11
Speaker 1: an experimental question and a theoretical question. It's an experimental
7:14
Speaker 1: question like could we see a singularity, what would it
7:17
Speaker 1: look like? Can we find one? If they do exist?
7:20
Speaker 1: And a theoretical question like what would it mean if
7:22
Speaker 1: they can exist? What would it actually be like? And
7:25
Speaker 1: then we'll get into this. But like, people don't even
7:27
Speaker 1: agree about what a singularity is, that there's no singular
7:30
Speaker 1: answer or a definition. There's a duopoly of singularities. Man. Well,
7:35
Speaker 1: as usually, we were wondering how many people had heard
7:38
Speaker 1: these two words together, naked and singularity at the same time,
7:42
Speaker 1: And so, as usual, Daniel went out there into the
7:44
Speaker 1: internet to ask people if they knew what a naked
7:48
Speaker 1: singularity was. So thank you to everybody who have volunteered
7:51
Speaker 1: to answer questions without any preparation. And if you would
7:55
Speaker 1: like to similarly give answers to tough physics questions without
7:58
Speaker 1: using any reference materials, please write to us two questions
8:02
Speaker 1: at Daniel and Jorge dot com. So think about it
8:05
Speaker 1: for a second. If someone as you on the street
8:07
Speaker 1: or on the internet what a naked singularity is, what
8:11
Speaker 1: would you answer. Here's what people had to say. I
8:14
Speaker 1: have never heard of naked singularity, but I definitely know
8:18
Speaker 1: what naked means, and I think I know what you
8:20
Speaker 1: mean by singularity, so I would imagine it has something
8:24
Speaker 1: to do with the very earliest of universe stripped of
8:27
Speaker 1: all forces. Singularity basically means when all the matter condenses
8:33
Speaker 1: down to one blob. For example, like all the gravitational
8:37
Speaker 1: force starts to attract all the matter and it just
8:40
Speaker 1: condenses down to one small blob, and that's you know
8:45
Speaker 1: how people say our universe is gonna end naked singularity? Um,
8:49
Speaker 1: I think might be when this blob doesn't feel any force,
8:54
Speaker 1: any other force from outside the singularity, so it might
8:57
Speaker 1: be naked to everything else in the universe. I'm not sure. Well,
9:02
Speaker 1: singularity is an intense amount of matter and energy in
9:07
Speaker 1: one point in space, so a naked singularity would be
9:12
Speaker 1: similarity that we could see like a center of a
9:15
Speaker 1: black hole if you if you took if you could
9:18
Speaker 1: just see into the center. I think it's something linked
9:22
Speaker 1: to a black hole. I think a naked singularity is
9:26
Speaker 1: something like a black hole without a short shirt radios,
9:29
Speaker 1: so a lot of mass on one point and it
9:32
Speaker 1: would not be heavy enough to keep light to itself.
9:35
Speaker 1: But I'm not sure if people agree upon if this
9:38
Speaker 1: can exist. Maybe this is a black hole without an
9:42
Speaker 1: event horizon, or maybe there's a start collapsing directly into
9:45
Speaker 1: a black hole without the supernova. Maybe there's something with
9:49
Speaker 1: other singularities, like technological singularity. All right, a lot of
9:54
Speaker 1: people linked it to black holes, which is what we
9:56
Speaker 1: were just talking about. And a lot of people had
9:59
Speaker 1: heard the to words separately, not together, naked and singularity,
10:03
Speaker 1: but maybe they had not heard of them together naked singularity. Yeah,
10:06
Speaker 1: but I think the name of this thing goes a
10:08
Speaker 1: long way to explaining it, as you can tell by
10:10
Speaker 1: people's answers that pretty quickly put together the idea that
10:14
Speaker 1: maybe a naked singularity is one that you could actually see,
10:17
Speaker 1: the one that isn't dressed by a black hole. All right,
10:21
Speaker 1: we'll step us through this, Daniel, First of all, what
10:23
Speaker 1: is a singularity? Because I think I know what naked means,
10:27
Speaker 1: and if you don't, I'm not going to be the
10:29
Speaker 1: one explaining it to you. I've known since I was born.
10:31
Speaker 1: I think, what's the definition of a singularity? And is
10:35
Speaker 1: there a singular definition of it? Yeah? So this is
10:37
Speaker 1: a fun question because you can have an idea about
10:40
Speaker 1: something before you have like a really precise, theoretical, crisp
10:44
Speaker 1: definition of what it is. And that's sort of the
10:46
Speaker 1: case here with singularity. That's sort of like the vague
10:49
Speaker 1: idea of a singularity, and then there's people trying to
10:52
Speaker 1: actually work out, well, what do we really mean, like
10:55
Speaker 1: mathematically when we talk about a singularity, And unfortunately there's
10:58
Speaker 1: not a whole lot of Chris definitions. It's sort of
11:01
Speaker 1: like two general ideas about what we mean about a
11:04
Speaker 1: singularity when we talk about in the theory, like in math.
11:07
Speaker 1: In the math and also in philosophy. Remember that almost
11:10
Speaker 1: every field of science in the end was born out
11:13
Speaker 1: of philosophy people thinking about tough questions and try to
11:16
Speaker 1: figure out, like how do we make progress on questions
11:18
Speaker 1: of like what is the universe? And eventually things get
11:22
Speaker 1: crisp enough and formed well enough and mathematical enough that
11:25
Speaker 1: like scientists can take over and actually make progress. So
11:28
Speaker 1: some of these things still are on the boundary between
11:31
Speaker 1: physics and philosophy because they're sort of like bubbling emerging questions.
11:35
Speaker 1: And that's the situation here with this question about what
11:38
Speaker 1: is a singularity? Yeah, so what are these two different
11:42
Speaker 1: ideas about what it is? You said, there's two, yeah,
11:44
Speaker 1: And so the first one is probably the one that
11:46
Speaker 1: comes to mind, and most people think about a singularity,
11:48
Speaker 1: and that's where the space sort of breaks down, where
11:51
Speaker 1: something in space becomes unphysical, it becomes like infinite, something
11:56
Speaker 1: that you figure like can't actually really happen. You know.
11:59
Speaker 1: For example, a black hole, we imagine might have a
12:02
Speaker 1: point at the center of it with an enormous amount
12:05
Speaker 1: of mass in a physical dot in a point with
12:08
Speaker 1: no volume, and that would be infinite density, and the
12:12
Speaker 1: curvature of space there is described by general relativity, would
12:15
Speaker 1: be infinite. And so we talk about that as a
12:18
Speaker 1: singularity because general relativity breaks down there where the curvature
12:22
Speaker 1: of space becomes infinite. Yeah. I think it's sort of
12:25
Speaker 1: related to infinity, right, because infinity is pretty much kind
12:29
Speaker 1: of the only thing that can break down math, right,
12:31
Speaker 1: Like we don't really understand it, or it's sort of
12:35
Speaker 1: like not defined in math, right. Yeah. In some cases though,
12:38
Speaker 1: it depends on the application, Like and sometimes when physics
12:42
Speaker 1: gives you an infinity, you say, well, that's wrong, that's nonsense,
12:45
Speaker 1: that can't happen. Although other times in physics you can
12:47
Speaker 1: have infinities, like the universe might be infinite in extent,
12:52
Speaker 1: it might go on forever in every direction, and that
12:54
Speaker 1: doesn't violate any principle of physics. It would mean the
12:57
Speaker 1: universe has an infinite amount of energy in it, right,
13:00
Speaker 1: Or the universe could have existed for an infinite amount
13:03
Speaker 1: of time or could exist for an infinite amount of
13:05
Speaker 1: times into the future. So sometimes infinity is allowed in physics,
13:10
Speaker 1: not a big deal. Other times it doesn't work, and
13:13
Speaker 1: it just depends on the theory. And in the case
13:16
Speaker 1: of a black hole. The reason that we don't like
13:18
Speaker 1: the infinity is that we describe what happens to space
13:22
Speaker 1: and things moving through space based on how space is curved,
13:25
Speaker 1: like how much is space bent by the presence of mass?
13:29
Speaker 1: And you know, for example that like space around the
13:31
Speaker 1: Sun is curved a little bit, which makes it natural
13:34
Speaker 1: for an object like the Earth to move in a
13:36
Speaker 1: circle around the Sun instead of what we would see
13:38
Speaker 1: as a straight line. So you can make predictions about
13:41
Speaker 1: what happens to something that moves through curved space. But
13:44
Speaker 1: you can't do that if the curvature is infinite, Like
13:47
Speaker 1: the equations just don't work. They give you nonsense answers.
13:50
Speaker 1: And so the theory general relativity breaks down when the
13:53
Speaker 1: curvature becomes infinite. So we call that a singularity of
13:56
Speaker 1: space time. Right, it seems like it it comes to
13:58
Speaker 1: singularity when something gets infinite in like a very short
14:02
Speaker 1: amount of space or a short amount of time. Maybe
14:05
Speaker 1: could that be sort of the one way to define
14:07
Speaker 1: it or to understand it. Yeah, And it really can
14:09
Speaker 1: be almost anything that can become infinite. You know, for example,
14:13
Speaker 1: you can have an electron. Electron is a point particle
14:16
Speaker 1: and it has a charge to it, and you can ask,
14:19
Speaker 1: for example, what is the electric field around an electron? Well,
14:23
Speaker 1: it depends on the distance you are from the electron.
14:26
Speaker 1: But if the electron is a point particle, then you
14:28
Speaker 1: can get as close as you want to it right
14:31
Speaker 1: that distance can basically go to zero, which means that
14:34
Speaker 1: the electric field or the force from the particle becomes infinite.
14:38
Speaker 1: And so you can find these singularities not just in
14:41
Speaker 1: sort of crazy exotic situations like the center of a
14:44
Speaker 1: black hole, but also in fairly simple, straightforward situations like
14:48
Speaker 1: an electron with all electrons are singularity. Is that what
14:51
Speaker 1: you're saying, or mathematically, that's what the math would tell you.
14:56
Speaker 1: So real electrons are not singularities, and that's because the
14:58
Speaker 1: simple mathematical description just gave you isn't the right one.
15:02
Speaker 1: What really happens when you get close to an electron
15:04
Speaker 1: is that it creates lots of other particles around its photons,
15:07
Speaker 1: which turned into quantum fluctuating positron electron pairs. We talked
15:11
Speaker 1: about this on another episode. Is called renormalization, where you
15:14
Speaker 1: redefine what it means to be the particle, and the
15:16
Speaker 1: particle becomes not just a point but a bunch of
15:20
Speaker 1: quantum mechanicals froth slashing around that point, and that becomes
15:23
Speaker 1: our definition of the particle, which in effect limits how
15:26
Speaker 1: close you can get to it. So quantum mechanics sort
15:29
Speaker 1: of covers up the singularity there prevents a singularity from happening.
15:33
Speaker 1: But in classical electromagnetism, if you just really did have
15:36
Speaker 1: an electron with a point particle, that would be a singularity.
15:40
Speaker 1: And so that's an example of how we don't think
15:42
Speaker 1: that singularity actually happens in the universe because electrons are
15:45
Speaker 1: not infinitely powerful points of charge. Okay, so that's one
15:49
Speaker 1: definition of a singularity. It's like when something goes infinite
15:52
Speaker 1: in a small amount of space or a short amount
15:55
Speaker 1: of time. So what's the other definition of a singularity. Well,
15:58
Speaker 1: there's this definition in philosophy of a singularity in space,
16:01
Speaker 1: which is a path that is not extendable. Like you
16:04
Speaker 1: can imagine moving through the universe and you can just
16:07
Speaker 1: keep going right in the path you're on, can just
16:10
Speaker 1: keep going, Well, what if you came to a spot
16:12
Speaker 1: where your path just couldn't go anymore? And this, for example,
16:15
Speaker 1: is what happens to a photon that falls into the
16:17
Speaker 1: singularity inside a black hole or right doesn't go anywhere anymore.
16:21
Speaker 1: It's not some other part of space. It goes to.
16:24
Speaker 1: So it's like another way to look at a singularity.
16:26
Speaker 1: It's like a weird deformation and sort of the arrangement
16:30
Speaker 1: of space itself. I mean like a like a stub
16:32
Speaker 1: in space, kind of like an abrupt end to space.
16:36
Speaker 1: That's also called a singularity. Yeah, an abrupt end to space.
16:39
Speaker 1: It's sort of like imagining that space has a boundary,
16:42
Speaker 1: but instead of that boundary being like on the edge
16:44
Speaker 1: of the universe, like we're all in some huge universe
16:47
Speaker 1: that has you know, a crust to it, this is
16:49
Speaker 1: like a boundary that's in a point, like a weird
16:52
Speaker 1: spot in the universe, where like there's a point of
16:54
Speaker 1: space there that's just not there, so you can't like
16:57
Speaker 1: go there. It's a really weird idea. It's sort of
17:00
Speaker 1: hard to get your mind around, but it's in some
17:02
Speaker 1: ways equivalent to the other way of looking at a singularity.
17:06
Speaker 1: You mean like it could exist in space, like a
17:09
Speaker 1: stub inside of space. Yeah, it could exist in space
17:12
Speaker 1: and like like a belly button or so many jokes
17:16
Speaker 1: to make their absolutely, yeah, it could be just like
17:19
Speaker 1: a weird feature of space where a particle that passes
17:22
Speaker 1: into it doesn't emerge and that's another way to think
17:26
Speaker 1: of a singularity. Right, just like belly bus, you know,
17:28
Speaker 1: link goes in. When does it ever come out? Nobody knows.
17:31
Speaker 1: Eventually it makes a black hole unless you're an audy
17:34
Speaker 1: I guess. All right, well, now that's a good definition
17:38
Speaker 1: of singularity. Now let's get into what a naked singularity
17:42
Speaker 1: is and whether or not they're real. But first let's
17:45
Speaker 1: take a quick break. All right, we're talking about naked singularities, Daniel,
18:01
Speaker 1: and this is a safer work, right, we can talk
18:03
Speaker 1: about naked singularities. Nobody's gonna get into trouble. That's right.
18:06
Speaker 1: I had the singularity sign a waiver also, so we're
18:09
Speaker 1: allowed to use the description of it as naked without
18:11
Speaker 1: paying it any royalty. It's comfortable with itself, the singularity.
18:15
Speaker 1: It's not self conscious singularity, alright. So singularity is either
18:20
Speaker 1: like a stubb in space, like a belly button in space,
18:24
Speaker 1: or just anything that kind of goes infinite in a
18:27
Speaker 1: short amount of space or time. That's a singularity. So
18:30
Speaker 1: then what is the naked singularity? Like something that is
18:34
Speaker 1: like that, but it's not close, like it's not covered. Yeah, exactly,
18:40
Speaker 1: it's just that simple. The idea is what a weird
18:43
Speaker 1: thing to have in space? What is this bizarre thing
18:46
Speaker 1: at the center of a black hole? What actually happens there?
18:49
Speaker 1: And it's frustrating because black holes are always cloaked, right,
18:52
Speaker 1: you can't see what's inside a black hole? Is there
18:55
Speaker 1: singularity in there? Is there not? Is there something else
18:57
Speaker 1: we're going on? We want to know? It? Frustrated and
19:00
Speaker 1: have this weirdest part of space be hidden from us
19:03
Speaker 1: by the event horizon. So then the question is it
19:07
Speaker 1: possible to have a singularity that's naked, that's revealed to us,
19:10
Speaker 1: a singularity that you could see from the outside, you
19:13
Speaker 1: know that you could visit and investigate and then report
19:17
Speaker 1: back to other people and maybe get some answers about
19:20
Speaker 1: the nature of the universe and what it can and
19:22
Speaker 1: can't do. Right, Well, the problem with the black hole
19:24
Speaker 1: singularity is that it bends space and time, and so
19:27
Speaker 1: it traps light, so we can't and everything else, and
19:31
Speaker 1: so therefore we can see it or get any information
19:34
Speaker 1: out of it. Right, Yeah, that's exactly right. The thing
19:37
Speaker 1: that creates the singularity is an extraordinary density of mass,
19:41
Speaker 1: and that mass also creates curvature of space around it,
19:45
Speaker 1: which creates an event horizon, right, it means that there's
19:48
Speaker 1: some point after which space has bent so much that
19:51
Speaker 1: every direction forward, every path forward, eventually leads to the
19:55
Speaker 1: center of the black hole. And you know, remember, the
19:57
Speaker 1: event horizon itself is not like a physical objects. It's
20:00
Speaker 1: just like a surface in space where once you pass it,
20:03
Speaker 1: there's just no way to ever avoid hitting the singularity.
20:07
Speaker 1: But it does mean that nothing that passes it can
20:10
Speaker 1: emit light out of it, which means we can get
20:12
Speaker 1: no information about what's going on beyond the event horizon.
20:15
Speaker 1: That's what's so frustrating, because of course all love to
20:18
Speaker 1: study the singularity, to see it, to row it, to
20:21
Speaker 1: shoot particles at it, to hit it with a tennis
20:23
Speaker 1: racket or whatever, but as long as it's behind an
20:25
Speaker 1: event horizon, we can't do that, right, And so a
20:28
Speaker 1: naked singularity then would be a singularity, but one that
20:30
Speaker 1: you can actually like walk up to and get right
20:34
Speaker 1: up next to it and look at it through a
20:36
Speaker 1: magnifying glass and coke at it. Right, Yeah, exactly, that's
20:39
Speaker 1: the idea. So if you have a picture in your
20:41
Speaker 1: mind of sort of like the rubber sheet of space
20:44
Speaker 1: where space gets bent by heavy mass, and the curvature
20:47
Speaker 1: grows very very rapidly as you get close to the
20:49
Speaker 1: black hole and then sort of goes to infinity at
20:52
Speaker 1: the center of the black hole. Then image you should
20:54
Speaker 1: have in your mind for naked singularity is more like
20:57
Speaker 1: just a pin prick, like a point, like space is
21:00
Speaker 1: mostly flat around the singularity, and then there's just this
21:03
Speaker 1: point where the curvature goes to infinity very very quickly, right,
21:06
Speaker 1: like a belly button, Just like a belly button. They
21:08
Speaker 1: should have called this a belly button of the universe. Yeah,
21:11
Speaker 1: bellybutton singularity. And in fact it works on multiple levels
21:14
Speaker 1: because the same way that a belly button tells you
21:17
Speaker 1: about like the origin of a person, it teaches you
21:19
Speaker 1: but like their origin story and how they were created
21:21
Speaker 1: through the placenta. Then a belly button singularity of the
21:24
Speaker 1: universe can tell you something about the origin of the
21:26
Speaker 1: universe because it teaches you about space, time and maybe
21:29
Speaker 1: even helps you understand the Big Bang. Right, And so
21:32
Speaker 1: I think belly button really is a great name for it.
21:34
Speaker 1: I think now you just tress it too far there.
21:37
Speaker 1: That was a little too much. But anyways, it is
21:40
Speaker 1: sort of like something in space. So I guess the
21:42
Speaker 1: question is, can you have a singularity without a black hole?
21:46
Speaker 1: Or maybe you can have other kinds of singularities that
21:48
Speaker 1: you could see, Yeah, exactly, And so that's the idea,
21:51
Speaker 1: and people are embarked on this sort of like theoretical exploration.
21:54
Speaker 1: They're like, can I make one in theory? Can I
21:58
Speaker 1: satisfy Einstein's equations of the universe and have a naked singularity?
22:04
Speaker 1: So it's like a way to explore the universe without
22:06
Speaker 1: ever leaving your living room, just like can I arrange
22:09
Speaker 1: this in reality? And you know, that's how black holes
22:11
Speaker 1: were discovered, basically, as people trying to figure out, like, well,
22:14
Speaker 1: we have these equations for how space and time bend
22:17
Speaker 1: in response to mass, would they allow the creation of
22:21
Speaker 1: this weird object. Let's see if the math says yes.
22:23
Speaker 1: And the math said yes, And so that's where we
22:25
Speaker 1: are with naked singularities, this sort of like exploring how
22:28
Speaker 1: you might be able to make one, to figure out
22:31
Speaker 1: is possible, is it allowed? What would it mean if
22:33
Speaker 1: it is allowed, what would it mean if it isn't allowed?
22:36
Speaker 1: All that sort of stuff, And so there's various ways
22:38
Speaker 1: people have thought of theoretically to try to manufacture a
22:41
Speaker 1: naked singularity in the equation right, Well, is it even
22:44
Speaker 1: possible to have like basically a black hole without the
22:47
Speaker 1: black hole? Can you have a singularity in space time
22:50
Speaker 1: just like a black hole, but not have the black
22:53
Speaker 1: you know, trap around it? Is that possible? The short
22:56
Speaker 1: answer is, we don't know. Some people think it's impossible,
23:00
Speaker 1: absolutely impossible. Some people think it might still be possible.
23:03
Speaker 1: And there's lots of areas of investigation and sort of
23:05
Speaker 1: a few paths people are going down and exploring the
23:08
Speaker 1: idea of a naked singularity, and one is to create
23:11
Speaker 1: a singularity using a black hole and then try to
23:15
Speaker 1: remove the event horizon. What do you mean, how can
23:17
Speaker 1: you remove the event horizon? Yeah, it's people actually writing
23:21
Speaker 1: about this all the time. They ask like, could you
23:23
Speaker 1: destroy a black hole? And we usually we say no,
23:26
Speaker 1: but we actually had a whole episode about how to
23:28
Speaker 1: destroy a black hole. And there is one possible way
23:32
Speaker 1: you could strip away the event horizon, and that's if
23:34
Speaker 1: you make the black hole spin really really fast. Because
23:38
Speaker 1: remember that black holes are not just heavy objects that
23:41
Speaker 1: curve space. The way that space gets curved is actually
23:44
Speaker 1: quite complicated and depends not just on like how much
23:47
Speaker 1: mass is there, but on its arrangement, and also on
23:50
Speaker 1: how fast it's spinning, because angular momentum contains energy, and
23:55
Speaker 1: space bends not just in response to mass, but also
23:58
Speaker 1: in response to energy. And there's one class of black holes.
24:02
Speaker 1: They're called curb black holes k E r R. And
24:05
Speaker 1: these black holes are spinning. Now, if you take that
24:08
Speaker 1: black hole and you convert a lot of its energy
24:11
Speaker 1: into spin, you like, drop something into it which has
24:14
Speaker 1: a lot of angle momentum but not a lot of mass,
24:17
Speaker 1: and you can bring the angular momentum up past a
24:20
Speaker 1: certain level, then the equations predict that the event horizon
24:24
Speaker 1: will shrink until eventually it hits the singularity and reveals
24:27
Speaker 1: the singularity. Wait, what too? More energy makes the black
24:32
Speaker 1: hole smaller? Isn't that weird? Doesn't usually more mass and
24:35
Speaker 1: energy make the black hole bigger? Yeah? Exactly? How to
24:39
Speaker 1: spinning it more? Make it small? What you need to
24:41
Speaker 1: do is somehow get it to convert its existing mass
24:44
Speaker 1: into spin. So it's not just about adding another object
24:48
Speaker 1: which is going to add overall mass. You need to
24:50
Speaker 1: somehow get it to convert its energy into spin. Because
24:55
Speaker 1: the location of this event horizon depends on the spin
24:58
Speaker 1: and on the mass, so you have to somehow do something,
25:01
Speaker 1: and nobody knows how to do this, which is like
25:03
Speaker 1: totally speculating. Somehow get this black hole to turn its
25:06
Speaker 1: mass into spin. And if you do that, they think
25:09
Speaker 1: the singularity will remain at the center, but the event
25:12
Speaker 1: horizon will essentially shrink because you're reducing the effective mass
25:15
Speaker 1: by just turning it into England momentum. Oh wow, but
25:18
Speaker 1: you would have to convert all of its mass into spin,
25:21
Speaker 1: right or just or some of it, just some of it.
25:23
Speaker 1: You need to cross some threshold. But if you read
25:25
Speaker 1: the papers about how to do this, they say, like, physically,
25:28
Speaker 1: we don't think bus is possible. So it's sort of like, well,
25:31
Speaker 1: the equations predict that if you violated this basic principle
25:35
Speaker 1: then the event horizon would disappear. That doesn't mean it's possible.
25:38
Speaker 1: It's just sort of like there's a region of theoretical
25:41
Speaker 1: space there where maybe if you could fix one problem,
25:44
Speaker 1: you might be able to get into this interesting region
25:46
Speaker 1: where the event horizon becomes part of the singularity. Can
25:50
Speaker 1: you maybe make a black hole and make it mostly
25:52
Speaker 1: out of spin, you know, like if you take a
25:54
Speaker 1: whole bunch of I don't know, fidget spinners and frisbees
25:58
Speaker 1: and tops, you know, and threw them out, spun them,
26:01
Speaker 1: throw them all together to make a black hole. Would
26:03
Speaker 1: that make a naked singularity that would still have more
26:06
Speaker 1: mass than angular momentum, and so it would be a
26:08
Speaker 1: spinning black hole and it would have a ring singularity
26:11
Speaker 1: at the heart of it, but it would still have
26:12
Speaker 1: an event horizon. So you need to somehow get a
26:15
Speaker 1: black hole that has like more angular momentum than mass itself,
26:19
Speaker 1: which is pretty hard to arrange and maybe impossible. All right,
26:23
Speaker 1: So that's one possibility, doesn't seem very likely. What are
26:27
Speaker 1: other ways we could maybe make a naked singularity. Another
26:30
Speaker 1: way to maybe make a naked singularity is to find
26:33
Speaker 1: a white hole. We talked about this also once on
26:36
Speaker 1: the podcast. A white hole might be like the opposite
26:39
Speaker 1: of a black hole. A black hole is a region
26:42
Speaker 1: in space where if something falls in, it can't ever leave,
26:45
Speaker 1: and a white hole is a region of space where
26:47
Speaker 1: things can only leave right they can't enter. And so
26:51
Speaker 1: a white hole in general relativity is sort of like
26:54
Speaker 1: the time reversal of a black hole. Like take a
26:58
Speaker 1: black hole as a star collapses and forms an event
27:02
Speaker 1: horizon and things get sucked into it. A white hole
27:05
Speaker 1: is like something that goes the opposite direction, like spews
27:09
Speaker 1: stuff out and then eventually boom, A star appears. Interesting.
27:13
Speaker 1: Now does it have a an event horizon like a
27:17
Speaker 1: black hole or is there such a thing as that
27:19
Speaker 1: the opposite of a event horizon. So it wouldn't have
27:22
Speaker 1: an event horizon. It would just be like a point
27:24
Speaker 1: in space where stuff is coming out of right, Like
27:27
Speaker 1: things are just flying out of this white hole the
27:29
Speaker 1: way like things fall into a black hole, things come
27:32
Speaker 1: out of a white hole. And we sometimes think of
27:34
Speaker 1: a white holes like the other end of a wormhole.
27:37
Speaker 1: You have a black hole connected through space somehow be
27:41
Speaker 1: a wormhole to a white hole and things that fall
27:43
Speaker 1: into the black hole and come out of the white hole.
27:46
Speaker 1: And so the white hole would be like a naked singularity,
27:48
Speaker 1: be at this weird point in space where you know,
27:51
Speaker 1: some of these metrics of spacetime become infinite, but not
27:54
Speaker 1: surrounded by an event horizon. I mean you can see it.
27:56
Speaker 1: Stuff is coming out of it at you. It's emitting light,
27:59
Speaker 1: or old socks or typewriters or whatever is coming out
28:02
Speaker 1: of this white hole. You can see those things, and
28:05
Speaker 1: so you can observe it. And so in that sense,
28:07
Speaker 1: it's a naked singularity because it's a singularity and it's
28:10
Speaker 1: something you can actually look at. Right, it would just
28:12
Speaker 1: look like a really bright pinpoint, right, like a star,
28:15
Speaker 1: but really really small. Yeah, And it might look like
28:18
Speaker 1: a bright pinpoint if it happens to be emitting gamma
28:21
Speaker 1: radiation or whatever, but it might also just look dark
28:23
Speaker 1: at some points if it's not giving off anything. You
28:25
Speaker 1: can't predict what a white hole is going to give
28:28
Speaker 1: out because it depends on what's inside the black hole
28:31
Speaker 1: it's linked to, and that's not something we can know. Okay,
28:35
Speaker 1: so that could also be a naked singularity. Are there
28:37
Speaker 1: any other possibilities can you have? I don't know, like
28:41
Speaker 1: an infinite charge somehow accumulated, or something else that doesn't
28:46
Speaker 1: bend spacetime. Well, really, the only kinds of singularities we
28:49
Speaker 1: can consider our gravitational ones, because everything else, like charge
28:53
Speaker 1: and particles, these are governed by quantum theory, and quantum
28:56
Speaker 1: theory prevents these kind of singularities by having uncertainty and
28:59
Speaker 1: by having fluctuations from random particles. The reason for example,
29:03
Speaker 1: an electron doesn't actually have negative infinite charge is because
29:06
Speaker 1: it creates this swarm of particles that surrounds it. And
29:10
Speaker 1: so quantum mechanics doesn't really allow for singularities in the
29:13
Speaker 1: same way. So they all have to be sort of
29:15
Speaker 1: gravitational or like geometric. Singularities of space time have to
29:19
Speaker 1: be about like the shape and structure of the universe.
29:22
Speaker 1: And so, for example, the Big Bang was a singularity, right,
29:25
Speaker 1: that's a timelike singularity. It is one that existed and
29:28
Speaker 1: no longer exists at the moment in time when the
29:31
Speaker 1: universe had essentially infinite density, and that was definitely naked
29:35
Speaker 1: because if you were around at the Big Bang you
29:37
Speaker 1: could have seen it. Yeah, I suppose. I don't know
29:40
Speaker 1: what it's like to observe if you're inside and infinite
29:43
Speaker 1: singularity of infinite density. I don't even know what that
29:46
Speaker 1: really means. It's like staring at your own belly Patty.
29:50
Speaker 1: It's like being inside an infinite belly button. And remember
29:53
Speaker 1: that general relativity doesn't tell us what happens during a singularity.
29:57
Speaker 1: General relativity tells us that, you know, space get denser
30:00
Speaker 1: and denser and denser, or a curvature gets infinite, but
30:03
Speaker 1: it breaks down at that point. You can't calculate with
30:05
Speaker 1: general relativity and say, what would happen if I did this,
30:08
Speaker 1: or if I had an eight ball flying through space
30:11
Speaker 1: and it hit a singularity, what would happen? It just
30:13
Speaker 1: cannot predict those things because general relativity breaks down when
30:17
Speaker 1: the curvature becomes infinite. So we need some new theory,
30:20
Speaker 1: something else to describe what would actually happen to physics
30:23
Speaker 1: of what would happen in a singularity. Alright, let's talk
30:26
Speaker 1: about whether or not naked singularities are real and if
30:31
Speaker 1: we could see one, what would they even look like?
30:33
Speaker 1: But first let's take another quick break. All right, we're
30:48
Speaker 1: talking about naked singularities being free, being visible, but also
30:55
Speaker 1: being almost infinite at the same time, and it sounds
30:58
Speaker 1: like there are a couple of possibilities. White holes or
31:02
Speaker 1: super spinning black holes are two possibilities. Daniel, you said
31:06
Speaker 1: there's another kind that could be out there, like a
31:07
Speaker 1: boundary point in space. Yeah. These are just points where
31:11
Speaker 1: a path of a particle ends. And this one, to
31:13
Speaker 1: me is like the most fun because I feel like
31:16
Speaker 1: we're sort of trapped in space like we're in this universe,
31:20
Speaker 1: we're in space. We're trying to understand what are the
31:22
Speaker 1: rules of this universe, but we're stuck sort of inside it,
31:25
Speaker 1: and it's hard to get your mind around the universe
31:28
Speaker 1: when you're looking at it from the inside. People are
31:30
Speaker 1: always asking us, like what is space expanding into or
31:33
Speaker 1: with outside of space? Because I think they're trying to
31:35
Speaker 1: grapple with the notion of the whole universe and its rules,
31:38
Speaker 1: and they want to do it by looking at it
31:40
Speaker 1: from the outside. And so if you can find like
31:43
Speaker 1: the edges of the universe, that gives you some sort
31:45
Speaker 1: of sense for like you know what the rules are,
31:47
Speaker 1: what the boundary conditions are. And so this this idea
31:50
Speaker 1: of a singularity is this like point in space. It's
31:53
Speaker 1: like a point that's an edge right where a particle
31:56
Speaker 1: flies in and just doesn't ever go anywhere else. It
31:59
Speaker 1: doesn't leave not there anymore. It's just there is no
32:02
Speaker 1: more space. So to me, this is one of the
32:04
Speaker 1: most fun ideas because it's hardest to think about, but
32:07
Speaker 1: also if you could actually see it, you'd be like, whoa,
32:09
Speaker 1: what is this? There's like a wrinkle in space is
32:11
Speaker 1: like a literal belly button in space? What is going on? Yeah,
32:15
Speaker 1: it'd be like a prinkle, like a pinch in space. Yeah, exactly,
32:18
Speaker 1: like a pinch in space. I would love to see
32:20
Speaker 1: a pinch. But would it become a black hole though,
32:22
Speaker 1: like when things get trapped inside of it? Well, it
32:24
Speaker 1: depends on what made it right, Like, first of all,
32:27
Speaker 1: there's nothing inside it. If we're talking about a boundary
32:30
Speaker 1: point in space, the inside of the singularity is not
32:32
Speaker 1: part of the universe, Like the particle just doesn't exist anymore,
32:36
Speaker 1: Like it's gone from our universe, like it's gone. The
32:38
Speaker 1: path just ends, right, Like you can think about particles
32:41
Speaker 1: as having worldlines, like they move through space and time.
32:44
Speaker 1: The singularity is a point where, like a worldline ends,
32:47
Speaker 1: it doesn't exist anymore. It's not like in there and
32:50
Speaker 1: you can't see it. It's just not anywhere anymore. Like,
32:52
Speaker 1: so what would happen to the particle? It would bounce back,
32:55
Speaker 1: like it would have to back out, or would it
32:57
Speaker 1: really disappear from our universe? It would disappear or from
33:00
Speaker 1: the universe. That's what it means for your world line
33:02
Speaker 1: to end. In that second definition of a singularity as
33:05
Speaker 1: a non extendable path, that's what a singularity is, a
33:08
Speaker 1: point where a particle, if it hits it just doesn't
33:11
Speaker 1: continue anymore in existing, which is really weird and hard
33:14
Speaker 1: to think about. What happens to its energy? It just
33:16
Speaker 1: it's energy disappears from the universe exactly. We talked about
33:19
Speaker 1: in another episode recently about how general relativity doesn't require
33:24
Speaker 1: that energy is conserved. It literally is like falling into
33:27
Speaker 1: a hole. Yeah, but the question is can that thing
33:29
Speaker 1: actually exist? And this is the kind of thing people
33:31
Speaker 1: are trying to figure out, like our naked singularity is
33:34
Speaker 1: real in the sense experimentally, like do they actually exist
33:37
Speaker 1: out there in reality? Could we see them and study
33:40
Speaker 1: them the way we can black holes? Or do they
33:42
Speaker 1: even exist theoretically? Like can you construct the equation in
33:47
Speaker 1: a way that predicts that they do exist? Whether or
33:49
Speaker 1: not they actually do in reality is one question. Whether
33:53
Speaker 1: we can make equations self consistent that describe them mathematically
33:56
Speaker 1: is a second question, Right, Well, it seemed to work
33:59
Speaker 1: for black hole holes, like general relativity predicted black holes
34:03
Speaker 1: and they're sort of consistent and we've seen them, so
34:06
Speaker 1: doesn't that answer the question? Doesn't that mean yes, that
34:09
Speaker 1: we can't theoretically make these, except that we know that
34:11
Speaker 1: general relatively breaks down at the singularity, so we don't
34:14
Speaker 1: actually know if this is singularity there. Like we know
34:17
Speaker 1: the black holes are real, yes, but you don't have
34:20
Speaker 1: to have a singularity inside a black hole to have
34:22
Speaker 1: a black hole, right, We don't know if there's actually
34:25
Speaker 1: a singularity in there or not, or something else weird
34:28
Speaker 1: is going on. We don't have a theory that describes
34:30
Speaker 1: correctly what happens at the center of a black hole.
34:33
Speaker 1: So another theory, some quantum gravity theory like glue quantum
34:36
Speaker 1: gravity might give us a different description of some very
34:39
Speaker 1: dense mass that's bending space in a weird way that's
34:42
Speaker 1: not a singularity. So we know that the Big Bang happened,
34:46
Speaker 1: but we don't really understand what it was. And in
34:49
Speaker 1: the same way, we know that black holes exist, but
34:51
Speaker 1: we don't know what's inside them. So we don't actually
34:54
Speaker 1: have hard proof that there are those gravitational singularities inside
34:58
Speaker 1: a black hole, or we also and that proof that
35:00
Speaker 1: they don't exist, right, because that's right. It could be
35:03
Speaker 1: that quantum physics is wrong in general relativity does maybe
35:07
Speaker 1: work at the center of a black hole. Well, it
35:08
Speaker 1: could be that there's some kind of singularity at the
35:11
Speaker 1: center of a black hole. But we know that general
35:12
Speaker 1: relativity as it stands can't describe them. You know, it
35:15
Speaker 1: just basically gives up. It fails there. And that's why
35:19
Speaker 1: they're so fascinating because we'd love to see general relativity
35:21
Speaker 1: fail because how it failed, what actually happens there could
35:25
Speaker 1: give us a clue about how to fix it. That's
35:27
Speaker 1: why seeing a naked singularity would be so much fun,
35:30
Speaker 1: because it would be clues to like ten Nobel Prizes
35:33
Speaker 1: in an afternoon in a singular place, like an infinite
35:36
Speaker 1: concentration of Nobel prices. Yeah, and one of the ways
35:40
Speaker 1: that people explore this theoretically is they say, well, here's
35:43
Speaker 1: a universe. Can I figure out how to make that universe? So,
35:46
Speaker 1: for example, we just talked about having a hole in space,
35:49
Speaker 1: a place where paths end, and general relativity tells us
35:52
Speaker 1: that any configuration to space that smooth can exist, though
35:56
Speaker 1: it's sometimes tricky to figure out, like how do you
35:59
Speaker 1: arrange the mass to get that bending of space? And
36:02
Speaker 1: so what people are doing now is trying to figure out,
36:04
Speaker 1: like wealthy ioretically, can I construct a universe in which
36:07
Speaker 1: I have a naked singularity. And they're doing all sorts
36:09
Speaker 1: of complex simulations, and they figured out ways to make
36:13
Speaker 1: singularities happen in simulated universes, but not simulated universes like ours.
36:17
Speaker 1: Simulated universes with like five dimensions instead of three dimensions,
36:22
Speaker 1: or different dimensions that like roll up and bend Weirdly,
36:25
Speaker 1: nobody succeeded in making a theoretical naked singularity in a
36:28
Speaker 1: universe that looks like ours. I see, you need more dimensions,
36:33
Speaker 1: You need like some extra juice, Yeah, exactly, because the
36:36
Speaker 1: rules are different in other dimensions. Right, if you have
36:38
Speaker 1: five dimensional space or nineteen dimensional space, and the way
36:41
Speaker 1: space bends and twists and wiggles is totally different than
36:45
Speaker 1: an our universe. And this has led people to wonder, like,
36:48
Speaker 1: if it's so hard to make a naked singularity, maybe
36:50
Speaker 1: they're just impossible. And so there was this idea in
36:53
Speaker 1: nineteen sixty nine by Roger Penrose. Recently when the Nobel
36:57
Speaker 1: Prize for thinking deeply about singularities and black holes. It's
37:00
Speaker 1: called the cosmic censorship conjecture, and it's the idea that
37:04
Speaker 1: the universe will always hide a singularity, so no naked
37:09
Speaker 1: singularities can exist because the universe will always find a
37:11
Speaker 1: way to block you from seeing. There's a certain prudishness
37:15
Speaker 1: to the universe, and that's because you know, anything that
37:19
Speaker 1: is singular would distort spacetime so much that you could
37:22
Speaker 1: never see it. Is that kind of the idea. There
37:24
Speaker 1: isn't really a firm idea. It's just like this idea
37:27
Speaker 1: makes people uncomfortable, so maybe there's something in the universe
37:30
Speaker 1: preventing it from happening. And it's very similar to the
37:32
Speaker 1: idea people had about black holes. Like when people heard
37:35
Speaker 1: about black holes originally they're like, that seems bonkers. I'm
37:39
Speaker 1: sure that that situation will never arise, or something about
37:42
Speaker 1: the universe will prevent it from happening, just the way
37:44
Speaker 1: that like, electrons are not singularities because quantum physics prevents
37:48
Speaker 1: it from happening. There's something inherent. It's not like an accident,
37:51
Speaker 1: and it's not like a conspiracy. There's just something about
37:54
Speaker 1: an electron and quantum physics that prevents that from happening.
37:57
Speaker 1: So the ideas maybe there's something going on, but it's
38:00
Speaker 1: really just a conjecture. It's not like there's a good reason.
38:02
Speaker 1: It's just like, boy, I kind of hope the universe
38:05
Speaker 1: prevents this from happening. That was penn Rose's original idea.
38:08
Speaker 1: Oh I see, it's like he didn't want there to
38:11
Speaker 1: be singularity. Yeah, you felt uncomfortable. He's like, this doesn't
38:14
Speaker 1: seem right, and so there must be some reason why
38:17
Speaker 1: they don't exist. And it sparked a lively debate in
38:21
Speaker 1: the field. Since then, other giants of black Hole thought,
38:26
Speaker 1: Stephen Hawking and Kip Thorne and John Preskill were having
38:29
Speaker 1: like a debate about whether naked singularities could exist, and
38:33
Speaker 1: they decided to make a bet. And so Hawking bet
38:36
Speaker 1: Preskill and Thorn that naked singularities are impossible. But then
38:40
Speaker 1: how would you settle the bet? You would have to
38:42
Speaker 1: see one or not see one, which is you know
38:44
Speaker 1: that could never happen. Yeah. Well, actually I think they
38:48
Speaker 1: were even just wondering, like, theoretically, could you find a
38:50
Speaker 1: solution to the Einstein equations? Could you describe a universe
38:54
Speaker 1: theoretically that had a naked singularity in it and didn't
38:56
Speaker 1: break any other rules? And a few years later some
39:00
Speaker 1: guy in Vancouver came up with like one very specific,
39:03
Speaker 1: crazy universe in which you could get a naked singularity,
39:07
Speaker 1: and so Hawking was forced to concede the bet because
39:10
Speaker 1: of this very specific exception that everybody agreed you could
39:13
Speaker 1: never have in reality, and so he lost the bet.
39:16
Speaker 1: But then they reformulated the bet, you know, removing this loophole. Oh,
39:19
Speaker 1: I see, so you could have a singularity, just maybe
39:22
Speaker 1: not in our universe. Yeah, exactly in our universe. It's
39:25
Speaker 1: maybe impossible. To help, it's maybe impossible. But you know,
39:29
Speaker 1: there's two ways to explore the universe. One is like
39:31
Speaker 1: have an idea theoretically proved that it's possible theoretically, and
39:35
Speaker 1: then go and look for it to see if your
39:37
Speaker 1: idea is correct. And the other is to actually just
39:39
Speaker 1: go out and look for the stuff. Like if we
39:41
Speaker 1: saw a naked singularity, that would sort of settle a
39:44
Speaker 1: question of whether they're possible theoretically, and then the theorists
39:47
Speaker 1: would have some work to do to figure out how
39:49
Speaker 1: to describe it and what does it mean. And so
39:51
Speaker 1: maybe the more interesting thing is, like, let's just go
39:53
Speaker 1: look for one. What would it look like? Right? Yeah,
39:55
Speaker 1: I guess that's the last question I have here is,
39:58
Speaker 1: you know, what would a naked s gularity look like?
40:01
Speaker 1: Would it look naked. Would it look shiny, you know,
40:04
Speaker 1: would it look like a black hole? Would it would
40:06
Speaker 1: it just you know, look like a weird pension space.
40:09
Speaker 1: What should we be looking for? Yeah, well, people don't
40:11
Speaker 1: really have a clear idea. There's lots of different ideas
40:14
Speaker 1: about what a naked singularity would look like, because there
40:16
Speaker 1: are different ideas for what a naked singularity would be.
40:19
Speaker 1: For some people, it would look like nothing. It would
40:22
Speaker 1: just look like a little hole in space, and the
40:24
Speaker 1: only way to see it would be like to observe
40:26
Speaker 1: particles disappearing as they pass into it, as for sort
40:29
Speaker 1: of the boundary condition, and that'd be pretty tough. It
40:32
Speaker 1: would be infinitely small too, write like, you know, it
40:35
Speaker 1: would be maybe hard to see an electron like fly
40:39
Speaker 1: right into it. Yeah, exactly, So that's pretty tough to
40:42
Speaker 1: ever spot. Then there's the other kind of singularity, you know,
40:45
Speaker 1: that one that's like maybe a white hole where things
40:48
Speaker 1: can come out of it. These could produce massive amounts
40:51
Speaker 1: of radiation. As you said earlier, a white hole could
40:53
Speaker 1: be very very bright. They could be glowing. And some
40:56
Speaker 1: people think that this could be the actual explanation for
40:59
Speaker 1: some weird stuff we see in our universe. We see
41:02
Speaker 1: things like gamma ray bursts and fast radio bursts, sources
41:06
Speaker 1: of really intense radiation that currently do not have any
41:09
Speaker 1: explanation in known astrophysics, and so it's always very tempting
41:13
Speaker 1: to say, ah ha, here's this new weird thing I'm
41:15
Speaker 1: thinking about. Maybe it explains this old weird thing we've
41:18
Speaker 1: been seeing. So, you know, it's not a great argument,
41:21
Speaker 1: but the idea is that a naked singularity might be
41:24
Speaker 1: like a very very bright point, you might explain some
41:27
Speaker 1: of the mysterious sources of energy, right that we see
41:29
Speaker 1: in the universe. Yeah, exactly. You know, if we did
41:31
Speaker 1: see one, to be an opportunity to study something new,
41:34
Speaker 1: something we haven't ever seen before, something that follows the
41:37
Speaker 1: rules of the universe, but maybe different rules than we're
41:40
Speaker 1: familiar with, or follows them in a new way that
41:43
Speaker 1: we weren't aware it was possible, And that's a great
41:45
Speaker 1: opportunity to figure out, like, what are the underlying rules?
41:48
Speaker 1: How does this universe actually work? Yeah, it'd be great
41:51
Speaker 1: to see one because it would tell us a lot
41:53
Speaker 1: about general relativity and quantum physics and help us kind
41:57
Speaker 1: of figure out what's going on with the tool yeah,
42:00
Speaker 1: And just like the belly button tells you about where
42:02
Speaker 1: you came from, it could tell us about the origins
42:04
Speaker 1: of the Big Bang. You know, one of the most
42:06
Speaker 1: famous singularities in history, of course, is the Big Bang.
42:09
Speaker 1: We think that the universe probably had this moment of
42:12
Speaker 1: infinite density, but it's not something that we understand even theoretically,
42:15
Speaker 1: like we can't calculate what caused it or calculate what
42:19
Speaker 1: happens during the singularity. So being able to see one
42:22
Speaker 1: and study it would really give us a handle on that,
42:25
Speaker 1: and it might also really help us think about future singularities.
42:28
Speaker 1: Future singularities might exist like the Big Crunch, you know,
42:31
Speaker 1: we could be heading for a new singular right yeah,
42:34
Speaker 1: but not for a while though, right not until after
42:36
Speaker 1: this podcast drops at the very least, so I have
42:38
Speaker 1: time to clean my belly button. Yes, you definitely do.
42:41
Speaker 1: The idea there is that the universe could slow down
42:44
Speaker 1: its acceleration and turn around and collapse back into a
42:48
Speaker 1: tiny point. So there might be a new singularity in
42:50
Speaker 1: our future. And you know, there are other kinds of singularities,
42:54
Speaker 1: you know, Singularities are cases where things go infinite. So
42:57
Speaker 1: another potential future for the universe is something we all
43:00
Speaker 1: the big Rip, where the acceleration of the universe doesn't
43:03
Speaker 1: slow down, but it continues and accelerates and eventually goes
43:06
Speaker 1: to infinity, and that would also be a singularity. Be
43:09
Speaker 1: the other kind of singularity with the universe is torn
43:12
Speaker 1: apart at infinite sping, and then the whole universe would
43:15
Speaker 1: be a singularity. And then the whole universe would be
43:17
Speaker 1: a singularity, just like if we had a big crunch,
43:20
Speaker 1: you would have the whole universe as a singularity. That
43:22
Speaker 1: would be infinite density. The big Rip would be a
43:25
Speaker 1: singularity of infinitely accelerating expansion. Man. That would be like
43:29
Speaker 1: the universe ripping out its clothes and saying I have
43:32
Speaker 1: my naked singularity exactly, And neither is one that we
43:35
Speaker 1: want to experience. But maybe to get a better handle
43:38
Speaker 1: on what that would be like and when it might happen,
43:41
Speaker 1: it would be great to spot the naked singularity floating
43:44
Speaker 1: out there in space so we could study it and
43:46
Speaker 1: get a handle on how this universe works. All right, well,
43:49
Speaker 1: we should all keep an eye out for naked singularity.
43:52
Speaker 1: Let us know if you see a belly button floating
43:55
Speaker 1: in space, shiny one you know, stay away from the
43:57
Speaker 1: dark ones. All right, Well that was pretty you staying.
44:00
Speaker 1: I feel like I learned a lot about nakedness and
44:03
Speaker 1: singular poison space. Yeah, alright, So maybe the next time
44:06
Speaker 1: you look out into space, think about what could be
44:09
Speaker 1: out there hiding, what could maybe be right in front
44:12
Speaker 1: of you. There could be singularities and singular things and
44:17
Speaker 1: events in space right in front of our noses. Thanks
44:20
Speaker 1: for joining us, see you next time. Thanks for listening,
44:31
Speaker 1: and remember that Daniel and Jorge explained. The Universe is
44:34
Speaker 1: a production at I Heart Radio. For more podcast from
44:37
Speaker 1: my Heart Radio, visit the I Heart Radio Apple Apple Podcasts,
44:41
Speaker 1: or wherever you listen to your favorite shows.